Conspiracy
chatter was once dismissed as mental illness. But the prevalence of
such belief, documented in surveys, has forced scholars to take it more
seriously. Conspiracy theory psychology is becoming an empirical field
with a broader mission: to understand why so many people embrace this
way of interpreting history. As you’d expect, distrust turns out to be an important
factor.

and

The strongest predictor of general
belief in conspiracies, the authors found, was “lack of trust.”

and

More
broadly, it’s a tendency to focus
on intention and agency, rather than randomness or causal complexity.In extreme form, it can
become paranoia. In mild form, it’s a common weakness known as
the fundamental attribution error—ascribing others’ behavior to
personality traits and objectives, forgetting the importance of
situational factors and chance. Suspicion, imagination, and fantasy are
closely related.

The more you see the
world this way—full of malice and planning instead of circumstance and
coincidence—the more likely you are to accept conspiracy theories of
all kinds. Once you buy into the first theory, with its premises
of coordination, efficacy, and secrecy, the next seems that much more
plausible.

and

Psychologists
and political scientists have repeatedly demonstrated that “when
processing pro and con information on an issue, people actively denigrate the
information with which they disagree while accepting compatible
information almost at face value.” Scholars call this pervasive
tendency “motivated skepticism.”Conspiracy
believers are the ultimate motivated skeptics. Their curse is
that they apply this selective scrutiny not to the left or right, but
to the mainstream. They tell themselves
that they’re the ones who see the lies, and the rest of us are sheep.

This would seem to apply to True Believers, also. True Believers
tend to think they are the only ones who can see the TRUTH, and the
rest of us are just ignorant sheep.

"An introduction into the world of
conspiracy" - Christopher Thresher-Andrews"Towards a definition of ‘conspiracy
theory’" - Robert Brotherton"A
review of different approaches to study belief in conspiracy theories"
- Anthony Lantian"The
psychology of conspiracy theories blog -
http://www.conspiracypsychology.com""Has
the internet been good for conspiracy theorising?" - Michael Wood"The
detrimental nature of conspiracy theories" - Daniel Jolley

The second PSY-PAG article on the above list,
"Towards a definition of 'conspiracy theory'" poses an interesting
question:

The claim that members of the US
government were complicit in the attacks of September 11, 2001, for
instance, is generally branded a conspiracy theory (e.g. Dunbar
& Reagan, 2006; Grossman, 2006), yet the label is rarely applied to the
claim that members of al-Qaeda secretly planned and executed the attacks.
The two claims both postulate a successful conspiracy to commit the
attacks. Why is it that, in
popular discourse, the term conspiracy theory is applied to the former
but not the latter?

One amusing answer is:

The
situation has been likened to attempting to define pornography – a task
which forced US Supreme Court Justice Potter Stuart to conclude simply,
‘I know it when I see it’ (Byford, 2011).

But, the more comprehensive and useful definition is in this statement:

I define conspiracy theory as an
unverified claim of conspiracy
which is not the most plausible account of an event or situation, and with sensationalistic
subject matter or implications. In
addition, the claim will typically postulate unusually sinister
and competent conspirators. Finally,
the claim is based on weak kinds of evidence, and is epistemically
self-insulating against disconfirmation.

In other words, a "conspiracy theory" is typically implausible,
sensationalistic, gives the conspirators super-abilities, is based upon
weak evidence, and is so vague that it cannot be easily disproved.

The
article also contains this:

Conspiracy
theories are unverified claims.
Conspiracies have occurred throughout history, and occur in some form
every day – in politics, organised crime, insider dealing, scams, and
so on. Philosopher Charles Pigden points out that ‘if a conspiracy
theory is simply a theory which posits a conspiracy, then every
politically and historically literate person is a big-time conspiracy
theorist’ (Pigden, 2007, p.222). However, this is not how the label is
commonly used. The
term usually refers to explanations which are not regarded as verified
by legitimate epistemic authorities. The theory may be regarded as
indisputably true by those who subscribe to it, but this belief is
invariably at odds with the mainstream consensus among scientists,
historians, or other legitimate judges of the claim’s veracity.

I couldn't have said it better myself. It certainly fits ALL the
conspiracy theories related to the anthrax attacks of 2001 that I've
heard during the past 12+ years.

Conspiracy theories and
scientific theories attempt to explain the world around us. Both apply
a filter of logic to the complexity of the universe, thereby
transforming randomness into reason. Yet these two theoretical breeds
differ in important ways. Scientific
theories, by definition, must be falsifiable. That is, they must
make reliable predictions about the world; and if those predictions
turn out to be incorrect, the theory can be declared false. Conspiracy theories, on the other hand,
are tough to disprove. Their proponents can make the theories
increasingly elaborate to accommodate new observations; and,
ultimately, any information contradicting a conspiracy theory can be
answered with, “Well sure, that’s what they want you to think.”

I think those three articles are enough to confirm that
I'm
not the only one who views "conspiracy theorists" as outside of the
norm. Conspiracy theorists tend to think of themselves as part of
the majority, but, as I've written many times, they are just a fringe
group that the vast majority of the public doesn't take
seriously. I don't see anything in these articles that disagrees
with what I've been saying about conspiracy theorists for 12+ years.